Results of Phase I/II PROLONG-9FP trial program also demonstrate efficacy in treatment of bleeding episodes and improved pharmacokinetics of rIX-FP compared to current treatment options; recombinant albumin fusion platform forms basis of innovation

AMSTERDAM, July 3, 2013 /PRNewswire/ -- Data presented by CSL Behring today showed clinical efficacy of a once-weekly dosing regimen of recombinant fusion protein linking coagulation Factor IX with albumin (rIX-FP). Results of the study were presented during an oral session at the International Society on Thrombosis and Haemostasis (ISTH) congress in Amsterdam.

CSL Behring, in collaboration with its parent company, CSL Limited (ASX: CSL), is developing rIX-FP for the prophylaxis and treatment of bleeding episodes in patients with hemophilia B as part of the PROLONG-9FP clinical study program.

"Hemophilia B is characterized by factor IX deficiency, which prevents normal blood clotting. People with this condition require factor IX infusions two to three times a week to achieve a significant reduction in bleeding," said Professor Uri Martinowitz, Director of the Institute of Thrombosis and Hemostasis and the Israeli National Hemophilia Center at Chaim Sheba Medical Center in Tel Hashomer, Israel. "This trial showed that less frequent infusions were needed with CSL Behring's investigational rIX-FP compared to currently available FIX products used on-demand or prophylactically to prevent or treat bleeding episodes."

The trial enrolled 17 hemophilia B patients, 13 of whom received weekly prophylactic treatment for approximately 11 months, and four of whom received on-demand treatment only when bleeding occurred. All prophylaxis patients maintained weekly treatment for the entire study, with mean and median annualized spontaneous bleeding rates of 1.26 and 1.13, respectively. All bleeding was treated successfully with two or fewer infusions of rIX-FP, with 95.3 percent of events treated with a single infusion.

Following a single infusion of 25 IU/kg rIX-FP, the mean FIX activity level was 3.8 percent and 2.7 percent above baseline at day 7 and 14, respectively, and the half-life (time taken for half of the treatment to be eliminated or metabolized) of rIX-FP was 94 hours.